US 6,480,704 B1 · Method and arrangement for forming a transmission signal

Abstract

The invention relates to a method and arrangement for forming a amplitude and phase modulated transmission signal. One idea of the invention is that he modulation signal is formed of separate baseband signals controlling phase and amplitude modulation. A phase control signal (phi) is used for controlling a voltage controlled oscillator (10), from which there is further obtained a transmission frequency signal for the RF amplifier (5). By means of the amplitude control signal (A), there is controlled the amplification of the RF amplifier. From the output of the RF amplifier, there is created a feedback signal by means of a sampling circuit (6, 7), and said feedback signal is used separately for correcting both amplitude control and phase control, so that the transfer function of the arrangement is made linear. Thus the employed amplifier can be a nonlinear amplifier with a high efficiency, and yet a good phase and amplitude linearity is achieved by applying the described arrangement.

Claims11

Dependent claims

A method for forming an amplitude and phase modulated transmission signal, wherein

there are formed baseband amplitude modulation signal (A) and phase modulation signal (phi)(101),
there is formed a carrier frequency signal (102),
the phase of said carrier frequency signal is controlled on the basis of said phase modulation signal (102),
the carrier frequency signal is amplified in order to form a transmission signal (103), and
the amplification of said carrier frequency signal is controlled on the basis of said amplitude modulation signal (103),
characterised in that in addition,
the phase of the carrier frequency signal also is controlled on the basis of the carrier frequency signal after the last amplification step in order to correct the transmission signal phase (104), and
the absolute value of said amplification is controlled on the basis of the carrier frequency signal after the last amplification step in order to correct the transmission signal amplitude (105).

5 more elements

An arrangement for forming an amplitude and phase modulated transmission signal, comprising

means (1) for forming a baseband amplitude modulation signal (A) and a phase modulation signal (phi),
an oscillator (10) for creating a carrier frequency signal,
means for controlling the phase of the output signal on the basis of the phase modulation signal (9, 20, 21, 22),
an amplifier (5) for amplifying the carrier frequency signal and for creating a transmission signal, as well as
means (3, 4, 19) for controlling the amplification of said amplifier (5) on the basis of said amplitude modulation signal,
characterised in that said arrangement also comprises
means (6, 7, 9, 11-14, 21) for controlling the phase of the output signal of said oscillator on the basis of the output signal of the substantially last amplification step of said amplifier in order to correct the phase of the transmission signal, and
means (2, 6-8, 17) for controlling the amplification of said amplifier on the basis of the output signal of the substantially last amplification step in order to correct the transmission signal amplitude.

5 more elements

Dependencies are inferred from the claim text.

Method and arrangement for forming a transmission signal

Life of this patent

Method and arrangement for forming a transmission signal

Life of this patent

Abstract

Claims11